The Craspedosomatidse of North America. 85 



This ^enus is named for Captain Tliomas L. Casey, to 

 whom our thanks are due for a collection of Californian Myri- 

 apoda including this and other interesting forms. 



Caseya differs from Underwoodia in the more numerous ocelli 

 and pectinate lamellae, the entire absence of carinse, the pro- 

 nounced lateral stri8e,the slender anterior male legs, and the greatly 

 enlarged coxse of the seventh legs of the male. Many other differ- 

 ences of the same or less importance might be enumerated, such 

 as the shape of the modified coxse of the second and third pairs 

 of male legs, the slight modification of the coxae of the sixth 

 male legs, the process of the coxae of the tenth legs, and the 

 oblique carinae of the coxae of the tenth and following legs ; also 

 the form of the male genitalia and ninth male legs, for these dif- 

 ferences are not paralleled among the species of the other genera. 



On the other hand there can be no doubt that these two genera 

 form a natural group and have more affinity with the European 

 genus Chordeuma than with the other American tj^pes. 



The mandibular}^ cardo is apparently smaller and more coal- 

 esced than in Cleidogona; no sulcus is evident, but a suture 

 becomes apparent as the alcohol dries out. 



The body is somewhat more gradually tapering caudad, and 

 slightly less so cephalad than Cleidogona, which this form 

 much resembles in extei"nal appearance. The head is, however, 

 not wider than the first segment, and the whole appearance of the 

 animal is the most iuliform of any of our Craspedosomatidae. The 

 entire absence of carinae, the rudimentary character of the setig- 

 erous tubercles, which are sunk in depressions, as though to 

 more thoroughly dispose of them, and the presence of longi- 

 tudinal striations, also give force to the fact that in the iuliform 

 Craspedosomatidae we have another of the strange approximations 

 of external form between animals widely separated hy the more 

 important structural characters. 



Caseya Iieteropus sp. n. 



Body fusiform, broadest about the middle, narrowed gradually to both 

 ends. 



Vertex prominent, smooth and shining; a few scattered j)unctations (per- 

 haps the bases of hairs) ; posteriorly emarginate-excavate, with a short median 

 suture extending from the posterior margin and not reaching an imaginary 

 line connecting the eyes. 



